Chlorogenic acid

What is chlorogenic acid?

Chlorogenic acid is a polyphenol found in many plants, but it is especially concentrated in unroasted (green) coffee beans. Roasting breaks much of it down, which is why weight-loss supplements use green coffee bean extract as their source. Green coffee extracts also naturally contain caffeine unless they are decaffeinated.

What the research says

The NIH Office of Dietary Supplements explains that green coffee extract, probably because of its chlorogenic acid, inhibits fat accumulation in mice and may modulate glucose metabolism. In humans, however, it notes that only a few clinical trials have tested green coffee for weight loss, and all were of poor methodological quality. One meta-analysis of three trials using 180 to 200 mg a day of extract found a moderate average weight loss compared with placebo, but the reviewers flagged the low quality of every included study. ODS adds that another small trial claiming a benefit was strongly criticized.

A more recent 2023 meta-analysis of three randomized trials with 103 participants found that green coffee extract providing at least 500 mg a day of chlorogenic acid was associated with about 1.3 kg more weight loss than control. The authors themselves noted the small sample size and short duration and called for larger, longer trials.

Overall, the evidence suggests chlorogenic acid might have a small effect on weight, but the trials are too few and too weak to rely on.

How it’s used in supplements

Green coffee bean extract is usually standardized to a stated percentage of chlorogenic acids. In multi-ingredient liver or weight blends, the chlorogenic acid content is rarely disclosed, so it is unclear whether a product delivers anything close to 500 mg a day.

Green coffee beans naturally contain caffeine, as ODS notes, so non-decaffeinated extracts can cause typical caffeine effects such as jitteriness and trouble sleeping, particularly when combined with coffee, tea or other stimulant-containing products. People sensitive to caffeine, those with heart rhythm problems or high blood pressure, and anyone pregnant or breastfeeding should be cautious and speak with a doctor.

Bottom line: chlorogenic acid from green coffee has a plausible mechanism and a few positive trials, but the human evidence is small, short and of mixed quality. A possible weight difference of a kilogram or so over several weeks is the most that current studies suggest, and only at doses that may be much higher than those in multi-ingredient blends. It is not a reliable fat burner, and caffeine content should be considered when combining it with coffee or other stimulants.